Combined potentiometer and switching structure

ABSTRACT

A combined potentiometer and switching structure including wiper contacts fixed to a shaft and having contacting engagement with an annular resistor and a pair of switching rings. The wiper contacts are located coincident, or in phase relation. The switching rings are each provided with an interrupted area, such areas are located in an arc complemental to the arc of the resistor and are circumferentially spaced apart a distance not greater than the length of the resistor contacting surface whereby, during rotation of the shafts, circuits connected to the switch rings are opened at different positions with respect to the resistor wiping contact. Alignment openings in the rings accommodate a pin to permit proper positioning of the rings relative to one another and also provide a passage for a conductor upon removal of the pin once the rings are properly positioned and secured against displacement.

United States Patent [72] Inventors Charles M. Tygard;

James R. Cameron, both of West Covina, Calif. [21] Appl. No. 828,617 [22] Filed May 28, 1969 [45] Patented June 15, 1971 [73] Assignee Spectrol Electronics Corporation City of Industry, Calif.

(54] COMBINED POTENTIOMETER AND SWITCHING STRUCTURE 5 Claims, 6 Drawing Figs.

[52] US. Cl. 338/172, 338/146, 338/166, 338/174, 338/198 [51] Int. CL 1101c 5/08 [50] Field oISearch 338/118, 137,143,146,160,162,163,166,171-174,198, 200, 215

[56] References Cited UNITED STATES PATENTS 2,859,315 11/1958 Joemdt 338/137X 2,926,321 211960 Stein 338/137 2,929,040 3/1960 Barden 3,007,126 10/1961 Fraser ABSTRACT: A combined potentiometer and switching structure including wiper contacts fixed to a shaft and having contacting engagement with an annular resistor and a pair of switching rings. The wiper contacts are located coincident, or in phase relation. The switching rings are each provided with an interrupted area, such areas are located in an arc complemental to the arc of the resistor and are circumferentially spaced apart a distance not greater than the length of the resistor contacting surface whereby, during rotation of the shafts, circuits connected to the switch rings are opened at different positions with respect to the resistor wiping contact. Alignment openings in the rings accommodate a pin to permit proper positioning of the rings relative to one another and also provide a passage for a conductor upon removal of the pin once the rings are properly positioned and secured against displacement.

PATENTEU JUN1 5 |97| saw 1 OF 2 FIG. 2

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mvnw'nms. CHARLES M, TYGARD. BY JAMES H. CAMERON.

JMJZfl ATTORNEY.

PATENTED JUN] 5197: 3585.562

sums [1F 2 iN vm mR s. CHARLES H. TYGARD. Y JAMES H CAMERON.

' ATTORNEY.

COMBINED POTENTIOMETER AND SWITCHING STRUCTURE BACKGROUND OF THE INVENTION A combined potentiometer-circuit switching unit has been proposed wherein a common rotor supports both the switch actuator and the wiping contact for engaging the resistance coil of the potentiometer. When additional circuit switching functions are required, the housing becomes undesirably bulky. It has been suggested that a common mounting ring he employed for supporting two switching units. While such an arrangement will conserve space by reducing the length of the housing required, a simple inexpensive method of assembling the parts so that conductors located in inaccessible locations may be readily connected to the switch units is needed.

SUMMARY OF THE INVENTION This invention has to do with a combined potentiometer and circuit switching structure. The potentiometer is of the conventional annular type having a circular contacting surface engaged by a wiping contact fixed to a shaft. A second wiper contact is affixed to the shaft and is phased with the resistor wiper contact. This second contact engages a pair of conducting switch rings. A circuit is formed from the second wiper contact through each of the switch rings. The switch rings are formed with interrupted areas whereby, at different positions of the resistor wiper contact, the switching circuits are opened. U

More particularly, the invention is directed to a structural arrangement which is economical to manufacture and convenient to assemble to produce a device having very small overall dimensions.

In addition, the invention relates to a unique method of assembling the switch rings in the switch insulator whereby welding of electrical leads to the switch rings may be easily accomplished.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a structure embodying our invention;

FIG. 2 is an end elevation looking to the right, FIG. 1;

FIG. 3 is an enlarged sectional view taken on a line corresponding to line 3-3, FIG. 2.

FIG. 4 is a sectional view taken on line 4-4, FIG. 3;

FIG. 5 is an exploded view of the switch rings and resistor illustrating the orientation of such parts; and

FIG. 6 is a schematic diagram illustrating an arrangement of the resistor and switching rings.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus consists of a casing having sections 10, 11. The section 10 is formed with an end wall 12 having an inwardly extending cylindrical hub 13. The hub 13 is provided with a central aperture forming a bearing in which an enlarged portion 14 of an actuating shaft 15 is journaled.

The casing section 11 is provided with a discoidal closure 16 which is formed with a central aperture arranged in axial alignment with the aperture in the hub 13 and forming a second bearing for the shaft 15. The end member 16 is attached to the section 11 by a clamp ring 17.

A resistor 18 of substantially annular configuration is fixedly mounted in the section 11. The inner surface 20 of the resistor is a contact surface over which a wiper contact 21 is moved. The contact 21 is fixed on one end of an arcuate spring member 22, the opposite end of which is fixed to an arm 23 which, in turn, is fixedly secured to a sleeve 25 of insulating material fixedly secured to shaft 15. A collector ring 27 is attached in conductive relation to the arm 23 and is connected to a terminal 28 by a brush 30.

The casing section 10 is formed at its inner end with a cylindrical flange 33 formed with an annular shoulder 34. The casing 11 is formed with a circular flange 35 snugly engaging the flange 33 and abutting against the shoulder 34. The sections are held together by a clamp ring 37.

A pair of switching rings 38, 40 are fixedly mounted in the flange 33 of the casing section 10. In the arrangement disclosed, the switching rings are mounted in an annular insulation member 41, fixedly mounted in the flange 33 and having a flange or central rib 43 extending radially inwardly between the switch rings 38, 40. The inner contacting surfaces of the switch rings are engaged by a wiper contact 45 fixed on one end of an arcuate leaf spring member 46, the opposite end of which is fixed to an arm 47 which, in turn, is fixed to the sleeve 25.. A collecting ring 50 is fixed in conducting relation to the arm 47, and is connected to a terminal 53 by a brush 54. The collector rings 27, 50 are separated by a ring of insulating material 55. A

The contacting surface 20 of the resistor 18 extends circumferentially less than 360-in the structure shown about 325.

The switching rings 38, 40 are each fonned with an inter rupted area in their inner contacting surfaces. For economy in manufacture, these interrupted areas are preferably in the form of a notch 58 in ring 38, and a notch 60 in ring 40. The switch rings 38, 40 are fixed in the insulating member 41 with the notches 58, 60 spaced apart circumferentially a distance less than the circumferential extent of the effective contacting surface 20 of the resistor 18. It will be apparent rings 38 and 40 are duplicate parts. To obtain the relationship shown in FIG. 5, it is only necessary to invert one of the rings through an angle of 180.

The switch ring 40 is connected to a terminal by wire 71 conveniently extended through the apertures 63, '64 in the switching rings and member 41, see FIG. 3. The switching ring 38 is connected to a terminal 72 by wire 73. One end of the resistor 18 is connected to a terminal 75 by wire 76. Ac-* cordingly, a switchingcircuit is established from terminal 53 to terminal 70 through switching ring 40, and a second switching circuit is established through terminal 53 and terminal 72 through switch ring 38.

To provide for convenience in assembling the switch rings with the interrupted areas in the desired phase relation, the rings are formed with through apertures 63. The member 41 is formed with a through aperture 64 in the flange or central rib 43. The apertures 63, 64 are aligned and a pin is extended through the apertures. The rings are pressed into the member.

41, or otherwise secured therein, and the member 41 is pressed or otherwise secured as by applying adhesive material to the rings prior to the insertion of the pins, in the section 10.

The alignment pin is then removed and the wire 71 is run through the apertures and fixed to the ring 40. The sections 10, 11 are oriented and fixedly clamped together by the band In FIG. 6, the interrupted areas in the rings 38, 40 are indicated at 58, 60 and as being located coincident with the ends of the resistor 18. The wiper contacts 21, 45 are fixed in phase relation, see also FIG. 4. Accordingly, when the resistor wiper 21 is positioned at the right end of the resistor, the contact 45" is in register with the notch 58 in the switching ring 39. When the resistor wiper has been moved to the left end of the resistor, the contact 45 is in registration with the notch 60 in the switching ring 40. At intermediate positions of the wiper contacts, both switching circuits are energized.

It will be apparent that the interrupted areas of the switching means may be phased to provide interruption of the switching circuits at various preselected positions of the resistor wiper contact 21.

While we have described a preferred embodiment of our invention, it is to be understood the invention is not limited thereto since it may be otherwise embodied within the scope of the following claims.

We claim:

1. A combined potentiometer and switching structure comprising a casing, a shaft journaled in said casing, a resistor fixedly mounted in the casing and having an arcuate contact surface arranged concentrically of said shaft and extending less than 360, a resistor wiper contact fixed to said shaft and movable along said contact surface from one end thereof to the other upon rotation of said shaft, a terminal connected to one end of said resistor and a terminal connected to said wiper contact, an annular ring formed of dielectric material disposed in said casing, said ring having a central rib formed thereon, a pair of conducting switch rings mounted on said annular ring, each of said rings having a circular contacting surface arranged in concentric relation to said shaft, an arm fixed to said shaft and having a switch wiper contact means yieldingly engaging the contacting surfaces of said rings, said switch wiper contact means being located coincident with said resistor wiper contact, the contacting surface of each of said rings being formed with an interrupted area, said rings being fixedly mounted in said casing with said interrupted areas being spaced apart circumferentially a distance not greater than the circumferential extent of the contact surface of said resistor, a switching circuit including a wiper terminal connected to said switching wiper contact, and a terminal connected to one of said rings, a second switching circuit including said wiper conswitching circuit is open at another position of said resistor wiping contact, said switch ring and annular ring being provided with aligned openings accommodating a conductor after the rings are secured relative to each other.

2. A combined potentiometer and switching structure as set forth in claim 1, wherein said interrupted areas in said switch rings consist of notches formed in the contacting surfaces of said rings.

3. A combined potentiometer and switching structure as set forth in claim 1, wherein said switch wiper contact means consists of a one-piece contact engaging the contacting surfaces of both of said rings.

4. A combined potentiometer and switching structure as set forth in claim 1, wherein said interrupted areas of said switch rings are located respectively complemental to the ends of the contact surface of said resistor.

5. A combined potentiometer and switching structure as set forth in claim 1, wherein said switch rings are axially spaced apart by said annular ring fixedly mounted in said casing, said ring members and insulating member being formed with aligned passages for the reception of an aligning pin during assembly of the structure. 

1. A combined potentiometer and switching structure comprising a casing, a shaft journaled in said casing, a resistor fixedly mounted in the casing and having an arcuate contact surface arranged concentrically of said shaft and extending less than 360*, a resistor wiper contact fixed to said shaft and movable along said contact surface from one end thereof to the other upon rotation of said shaft, a terminal connected to one end of said resistor and a terminal connected to said wiper contact, an annular ring formed of dielectric material disposed in said casing, said ring having a central rib formed thereon, a pair of conducting switch rings mounted on said annular ring, each of said rings having a circular contacting surface arranged in concentric relation to said shaft, an arm fixed to said shaft and having a switch wiper contact means yieldingly engaging the contacting surfaces of said rings, said switch wiper contact means being located coincident with said resistor wiper contact, the contacting surface of each of said rings being formed with an interrupted area, said rings being fixedly mounted in said casing with said interrupted areas being spaced apart circumferentially a distance not greater than the circumferential extent of the contact surface of said resistor, a switching circuit including a wiper terminal connected to said switching wiper contact, and a terminal connected to one of said rings, a second switching circuit including said wiper contact terminal, and a terminal connected to the other of said rings, whereby one of said switching circuits is open at one position of said resistor wiper contact, and said other switching circuit is open at another position of said resistor wiping contact, said switch ring and annular ring being provided with aligned openings accommodating a conductor after the rings are secured relative to each other.
 2. A combined potentiometer and switching structure as set forth in claim 1, wherein said interrupted areas in said switch rings consist of notches formed in the contacting surfaces of said rings.
 3. A combined potentiometer and switching structure as set forth in claim 1, wherein said switch wiper contact means consists of a one-piece contact engaging the contacting surfaces of both of said rings.
 4. A combined potentiometer and switching structure as set forth in claim 1, wherein said interrupted areas of said switch rings are located respectively complemental to the ends of the contact surface of said resistor.
 5. A combined potentiometer and switching structure as set forth in claim 1, wherein said switch rings are axially spaced apart by said annular ring fixedly mounted in said casing, said ring members and insulating member being formed with aligned passages for the reception of an aligning pin during assembly of the structure. 